textproduct: Quad Cities

KEY MESSAGES

- Frost Advisory in effect late tonight through daybreak Saturday for much of the area north of a Kahoka, to Burlington, to Princeton IL line. Steps should be taken to protect any sensitive outdoor vegetation.

- Blocked pattern will maintain a general northwest flow across the region for much of the period, with embedded waves and fronts combining with diurnal instability/heating to produce almost daily chances of precip in or near the forecast area.

SHORT TERM /THROUGH TONIGHT/

Issued at 217 AM CDT Fri May 1 2026 An upper low was located over Ontario early morning with water vapor imagery showing several shortwaves rotating around the low and across the Midwest. One shortwave was shifting east of the area early this morning with clouds and spotty showers exiting owing to a brief bout of clearing. This has allowed temperatures to drop off into the 30s in some locations, and with diminishing wind could result in some patchy frost. However, this frost potential looks limited and transitory as the next shortwave upstream into NW Iowa is sliding E/SE with clouds quickly approaching. Another wave was noted diving southward through the eastern Dakotas. Overall, the DPVA attendant to the shortwaves will foster increasing clouds today along with a chance for showers (20-40%). Soundings show some elevated CAPE (100+ j/kg), which could lead to some thunder with the low topped convection but this should be fairly isolated with equilibrium levels warmer than -20c. Highs look to be in the 50s, with some lower 60s possible especially south where more solar insolation is anticipated.

Any showers should dissipate by mid evening, as the shortwave(s) depart. Increasing subsidence in the wake of exiting system and incoming weak surface high should bring about a decrease in clouds. This along with light winds will make for favorable conditions for frost, particularly north/west of a Burlington to Princeton, IL axis, where confidence is highest on a longer duration of clearing and weak winds fostering lows in the lower to mid 30s. As a result, a Frost Advisory has been issued for much of eastern Iowa, northeast Missouri and northwest Illinois. Can't rule out some cold drainage locations dropping to freezing or just below, but this would not appear to be for a climatologically long enough time to cause damage and necessitate a freeze warning. Still, anyone with sensitive outdoor plants should take precautions to protect them. Frost is possible south of a line from Burlington to Princeton, IL, but confidence is too low for a headline at this time, as probabilities for temperatures less than 36F are low due to the potential for cloud cover to linger the longest in this area. Will need to take a closer look today for any need on expanding the Frost Advisory.

LONG TERM /SATURDAY THROUGH THURSDAY/

Issued at 217 AM CDT Fri May 1 2026

An omega block off the Pacific coast looks to remain in place throughout much of the period. After a brief bout of westerly flow and moderating temperatures near to above normal Sunday and Monday, we should see a fairly persistent span of predominantly N/NW flow and cooler than normal temperatures heading through mid to late next week. In fact, per CPC days 6-10/8-14 temperature outlooks it appears this cooler pattern will persist through mid-May with more frost/freeze conditions possible, particularly around May 8th/9th. While some showery weather likely at times no heavy rain is expected, and overall CPC has the region favored for below normal precipitation. The NW flow should also preclude any organized severe weather potential for the area as well over the next 7+ days. That said there is a Marginal risk (level 1 of 5) for an isolated strong/severe storm Sunday PM. Confidence is low with this potential due to the presence of an EML and limited forcing for ascent.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 525 AM CDT Fri May 1 2026

Impacts:

- Isolated to scattered showers (20-40%). Low probability (20%) for thunder this afternoon into early evening. Spotty MVFR to localized IFR visibility is possible with the heavier showers and any isolated storms.

- Wind gusts 20+ kt possible in/near the showers this afternoon. Outside of showers winds will be potentially quite variable, but generally light at 10 kt or less.

Discussion:

A passing upper air disturbance(s) will bring VFR ceilings (4-8kft agl) and some showers into this evening. Residual dry air will likely result in predominantly sprinkles this morning with no impacts. Isolated to scattered showers, some with more robust cores and brief visibility reductions, are expected mainly in the 19z-02z timeframe. This has been handled with a PROB30 shower mention, and have left out any mention of thunder as the threat appears too isolated. Soundings show a somewhat favorable setup for gusty winds with a low level inverted-V profile in the presence of sub-cloud dry air. Evaporative processes may lead to some enhanced gusts in/near showers with soundings showing around 20 kt of wind above 850 hPa through 700 hPa. The precipitation should dissipate as the evening progresses given the loss of heating and also departure of the disturbance(s). This will be followed by decreasing clouds. Outside of any gusty winds near showers, winds look to be mainly light at 10 kt or less and could be rather variable particularly this morning and again later tonight and predominantly W/NW in between. Can't rule out some patchy radiational fog after 08z in areas that receive some measurable rain today. Confidence is too low for any mention at the TAFs at this juncture.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Frost Advisory from 1 AM to 8 AM CDT Saturday for IAZ040>042- 051>054-063>068-076>078-087-088-098. IL...Frost Advisory from 1 AM to 8 AM CDT Saturday for ILZ001-002- 007-009-015. MO...Frost Advisory from 1 AM to 8 AM CDT Saturday for MOZ009.